Low-water alarm



7 (No Model.)

T. A. DELANEY 85R. E. HILLS. LOW WATER ALARM.

No. 474,631. Patented May 10, 1892.

THOMAS A. DELANEY AND ROBERT E. HILLS, OF CHICAGO, ILLINOIS.

LOW-WATER ALARM.

SPECIFICATION forming part Of Letters Patent N 0. 474,631, dated May 10,1892 Application filed February 18, 1892. Serial No. 421,927. (Nomodel.)

To all whom, it may concern.-

Be it known that we, THOMAS A. DELANEY and ROBERT E. HILLS, citizens ofthe United States, residing at Chicago, in the county of Cook and Stateof Illinois, have invented certain new and useful Improvementsin Low-Water Alarms, which are fully set forth in the following specification,reference being had to the accompanying drawings, in Which Figure 1represents a cross-section of a portion of a boiler with an alarmapplied thereto, partly in elevation and partly in vertical sect-ion,embodying our invention; Fig. 2, an elevation of the combinedfusible-plug holder and whistle detached; Fig. 3, a plan section takenon the line 3 3 of Fig. 1, and Fig. 4 a similar section taken on theline 4 4 of Fig. 1.

Our invention relates to a device for preventing the explosion ofsteam-boilers by the water therein falling below the safety-level, andparticularly to that class of devices in which an 0ntlet-pipe is stoppedby a steam fusible plug to which steam is admitted when the water fallsbelow a certain point.

We will describe in detailthe construction and operation of an alarm inwhich we have carried out our invention in one practical way; and theparticular improvements which we believe to be new and wish to secure byLetters Patent will be more definitely pointed out in the claims.

In the drawings, A represents a boiler pro vided with ordinary fines a.It will be understood that when in operation the water in the boilermust stand above the level of these fines, as indicated by the wordsWVater-lines in Fig. 1. The pipe B is set in the boiler in a suitableway and extended down a little below the water-line in the same. Thispipe is carried up above the boiler any convenient distance andsurmounted bya suitable valvecasing O, in which is mounted and properlyseated an ordinary two-way valve D, the port cl of which liesdiametrically through the valve, so that evidently communication withthe pipe below may be closed or opened according to the adjustment ofthe valve.

A small chamber in the shape of a cast bulb E is mounted on the top ofthe valvecase, the connection, as shown in the drawings, being made by athreaded socket c in the case, which receives a threaded stem 6 of thebulb, the latter being perforated of course and communicating with aport cl in the valve-case above the valve. At the upper end of the bulbE there is an enlarged head E, which extends upward from the bulb, is ofgeneral circular form, and is cut out to form a small circular recess orcup-shaped opening e,which is open at the top and communicates at thebottom by an aperture 6 with the bulb below. This aperture 6 is threadedto provide for the seating of a plug-holder F, which has a short stemthreaded to fit the said aperture. The plug-holder is surmounted by ahollow head Gr, which is preferably made in one piece with the holder.The upper portion of this head is enlarged, so that it nearly fills thecup, leaving between the two an annular slit g, like that usually foundin steam-whistles. The central opening f in the plug-holder communicatesdirectly with the interior of the head G and is stopped with a plug fofmetal, fusible at steam-heat. Preferably this plugopening and plug areslightly conical to give an enlarged head for steam-contact. Apertures gopen out radially from the interior of the head G to the space betweenthe cup and the latter, as seen in Fig. 1. The head is also providedwith a long stem 9, extending upward, and this stem is hollow, beingprovided with a passage 9 running its entire length, but constrictedatthe upper end to provide a very small opening 9 The lower end of thispassage 9 communicates with the central opening in the head and isarranged directly over the fusible-plug opening. The upper end of thestem is threaded for a little distance, as seen at g and an ordinarysteamwhistle bell 1-1 is mounted on the stem by means of a threadedaperture h in its upper end, through which the stem passes. The

bell is thus made readily detachable and may be secured in any positiondesired on the stem by means of a jam-nut h.

It is obvious that we have here combined a safety-plug of fusible metaland a steanistantially filled with water, the valve D being turned so asto communicate with the bulb E, which is also filled, or nearly so, withwater. If, however, the water in the boiler falls below the lower end ofthe pipe, the water therein runs out, steam enters and, coming incontact with the plug, fuses it, as'usual, and

thereby provides an escape for the steam into the head Gand thence outthrough the annular space 9, thereby sounding the whistle if the bell isin' place. It is evident that if the head G were made as usual insteam-whistles the netal'of the fusible plug would be driven into thelatter, thereby stopping'the ports and preventing the steam fromescaping more or less. The opening in the stem above the head is for thepurpose of obviating this difficulty. The fused metal will be blown upinto this space, thereby leaving the steam-outlets free. The opening'i'nthe stem'is constricted at its upper end to prevent the too rapid escapeof the steam therefrom, which would perhaps affect the operation of thewhistle. It will be seen that the holder for the fusible plug isessentially a part of the whistlethat is to say, it is made in one piecewith the head G, which, with its cup,is very much the same as inordinary'whistles.

In somelocations it may not be desirable to sound a whistle-forinstance, in schoolbuildings, or stores employing many youngpeople,where thesoundingof the whistle would very likely cause a panic.For this reason we make the bell detachable, so that in locations, suchas mentioned above, the bell may be removed, in which case the devicewill be operative just the same as before, except that there will be nowl1istle,'but only the hissing of escaping steam through the annularopening, which, however, will be sufficient to notify the attendants inthe boiler-room.-

Having thus described our invention, what we claim as new, and desire tosecure by Letters Patent, is

1. In a low-Water alarm, a main pipe extending down into the boiler, incombination with a fusible-plug holder set in the upper end of the pipeand provided with lateral passages above the plug-opening for the escapeof steam, and a passage directly overthe plug to receive the latter whenblown out, substantially as described.

2. In a low-water alarm, a main pipe 13, in

combination with the cup E, the hollow head G, set in said cup, with anannular opening between them, the fusible-plug holder F on. I

the lower end of said head and mounted at the upper end of the mainsteam-conduit, and

the hollow stem 9 arranged immediately and arranged just over thefusible plug, and

the bell H, detachably mounted on said stem, substantially as described.

4. In a low-water alarm, the main pipe 13 in combination with thevalve-case C, valve D,

bulb E, cup-shaped head E, hollow head and plug-holder FG, fusible plugf, and hollow stem g substantially as described.

THOMAS A. DELANEY. ROBT. E. HILLS.

Witnesses:

A. M. BEST, W. C. CORLIES.

